Effects of CO addition on laminar flame characteristics and chemical reactions of H2 and CH4 in oxy-fuel (O2/CO2) atmosphere

2020 ◽  
Vol 45 (39) ◽  
pp. 20472-20481 ◽  
Author(s):  
Yongliang Xie ◽  
Na Lv ◽  
Qizhang Li ◽  
Jinhua Wang
Keyword(s):  
Chemical Reactions ◽  
Laminar Flame ◽  
Co Addition ◽  
Co2 Atmosphere

A Comprehensive Experimental and Kinetic Study of Laminar Flame Characteristics of H2 and CO Addition to Oxygenated Gasoline

2021 ◽  
Vol 35 (17) ◽  
pp. 14063-14076
Author(s):  
Farha Khan ◽  
Ayman M. Elbaz ◽  
Jihad Badra ◽  
Vincent Costanzo ◽  
William L. Roberts
Keyword(s):  
Kinetic Study ◽  
Laminar Flame ◽  
Co Addition

scholarly journals On the laminar combustion characteristics of natural gas-syngas-air mixtures

2018 ◽  
Vol 22 (5) ◽  
pp. 2077-2086 ◽  
Author(s):  
Ning Zhang ◽  
Jie Liu ◽  
Junle Wang ◽  
Hongbo Zhao
Keyword(s):  
Thermal Diffusivity ◽  
Laminar Flame ◽  
Hydrodynamic Instability ◽  
Flame Temperature ◽  
Laminar Flame Speed ◽  
Flame Thickness ◽  
Mixture Density ◽  
Flame Instability ◽  
Co Addition ◽  
Flame Instabilities

In this study, the effects of hydrogen and CO addition on the laminar flame speed and flame instabilities of CH4/air mixture are investigated experimentally and numerically. Results show that laminar flame speeds increase almost linearly with the addition of hydrogen, which is mainly caused by the increase of the flame temperature and the thermal diffusivity of the mixture. However, it de-creases with the increase of the pressure, which is mainly due to the increase of the mixture density and the enhancement of the termination reactions. The hydrodynamic instability is increased with the increase of hydrogen ratio and pressure, which is due to the reduction of the flame thickness. With the increase of hydrogen fractions and pressure, the Markstein lengths decrease obviously, which means the flame instability is enhanced. The addition of CO has little effect on the flame speeds and flame instabilities.

Surface reactions observed by photoemission electron microscopy (PEEM)

1992 ◽  
Vol 50 (1) ◽  
pp. 286-287
Author(s):  
H.H. Rotermund
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Work Function ◽  
Chemical Reactions ◽  
Reaction Diffusion ◽  
Dynamic Processes ◽  
Clean Surface ◽  
Crystal Surfaces ◽  
Single Crystal Surfaces ◽  
Photoemission Electron

Chemical reactions at a surface will in most cases show a measurable influence on the work function of the clean surface. This change of the work function δφ can be used to image the local distributions of the investigated reaction,.if one of the reacting partners is adsorbed at the surface in form of islands of sufficient size (Δ>0.2μm). These can than be visualized via a photoemission electron microscope (PEEM). Changes of φ as low as 2 meV give already a change in the total intensity of a PEEM picture. To achieve reasonable contrast for an image several 10 meV of δφ are needed. Dynamic processes as surface diffusion of CO or O on single crystal surfaces as well as reaction / diffusion fronts have been observed in real time and space.

Microwaves: Application in Electron Microscopy

1990 ◽  
Vol 48 (3) ◽  
pp. 140-141
Author(s):  
Anthony S-Y Leong ◽  
David W Gove
Keyword(s):  
Electron Microscopy ◽  
Light Microscopy ◽  
Chemical Reactions ◽  
Electromagnetic Waves ◽  
Tissue Fixation ◽  
Primary Method ◽  
Dipolar Molecules ◽  
Wide Range ◽  
Time Required ◽  
Cryostat Sections

Microwaves (MW) are electromagnetic waves which are commonly generated at a frequency of 2.45 GHz. When dipolar molecules such as water, the polar side chains of proteins and other molecules with an uneven distribution of electrical charge are exposed to such non-ionizing radiation, they oscillate through 180° at a rate of 2,450 million cycles/s. This rapid kinetic movement results in accelerated chemical reactions and produces instantaneous heat. MWs have recently been applied to a wide range of procedures for light microscopy. MWs generated by domestic ovens have been used as a primary method of tissue fixation, it has been applied to the various stages of tissue processing as well as to a wide variety of staining procedures. This use of MWs has not only resulted in drastic reductions in the time required for tissue fixation, processing and staining, but have also produced better cytologic images in cryostat sections, and more importantly, have resulted in better preservation of cellular antigens.

Fine structure and properties of defects in naturally occurring silicates and oxides

1990 ◽  
Vol 48 (4) ◽  
pp. 460-461
Author(s):  
David R. Veblen
Keyword(s):  
Chemical Reactions ◽  
High Resolution Electron Microscopy ◽  
Extended Defects ◽  
Single Chain ◽  
Naturally Occurring ◽  
Resolution Electron ◽  
Fine Structures ◽  
Image Simulations ◽  
Similar Crystal Structure

Extended defects and interfaces control many processes in rock-forming minerals, from chemical reactions to rock deformation. In many cases, it is not the average structure of a defect or interface that is most important, but rather the structure of defect terminations or offsets in an interface. One of the major thrusts of high-resolution electron microscopy in the earth sciences has been to identify the role of defect fine structures in reactions and to determine the structures of such features. This paper will review studies using HREM and image simulations to determine the structures of defects in silicate and oxide minerals and present several examples of the role of defects in mineral chemical reactions. In some cases, the geological occurrence can be used to constrain the diffusional properties of defects.The simplest reactions in minerals involve exsolution (precipitation) of one mineral from another with a similar crystal structure, and pyroxenes (single-chain silicates) provide a good example. Although conventional TEM studies have led to a basic understanding of this sort of phase separation in pyroxenes via spinodal decomposition or nucleation and growth, HREM has provided a much more detailed appreciation of the processes involved.

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